Real-time Demonstration of the Change from Above/Below Based on the Corpus Data: Cases of Sa-Insertion, Ra-Deletion, and Re-Insertion in Japanese

This research investigates three ongoing language changes in Japanese: sa-Insertion, ra-Deletion, and re-Insertion, in light of the “change from above/below” (Labov 1990). Sa-Insertion involves a process, which adds an extra -asto the causative morpheme, yielding a double causative construction (1). Ra-Deletion involves a process which deletes -rain the potential morpheme (2). Re-Insertion involves a similar process to sa-Insertion where an extra –re is added to the potential morpheme, yielding a double potential construction (3).